Question

我有一个按ID1排序的表A： id1 id2

1          8
1          9        
3          5        
3          7
6          7
7          9

但我希望得到这个：

id1       id2
1          8
1          9
7          9    
3          5        
3          7
6          7

首先应该是id1的相等值，此后应该是id2的等值，依此类推

Answer 1

我认为这应该可以解决问题：

SELECT id1, id2 
FROM table 
ORDER BY (CASE WHEN id1 < id2 THEN id1 ELSE id2 END), id1, id2;

CASE WHEN id1 < id2 THEN id1 ELSE id2 END用于获取两个ID中的最低者（感谢@dnouth），您可以对此进行排序。

请参阅 this SQL Fiddle 以获取示例。

如果您使用Oracle，则可以尝试以下操作：

SELECT id1, id2 
FROM table 
ORDER BY LEAST(id1, id2), id1, id2;

请参阅 this SQL Fiddle 。

Answer 2

如果星号表示与前一行中的值有连接，那么这将适用于您的样本数据：

Oracle查询：

SELECT id1, id2
FROM   (
  SELECT id1, id2, ROWNUM rn
  FROM   (
    SELECT *
    FROM   (
      SELECT *
      FROM   table_name
      ORDER BY id1, id2
    )
    CONNECT BY NOCYCLE
       ( PRIOR id1 = id1 AND PRIOR id2 < id2 )
    OR ( PRIOR id1 < id1 AND PRIOR id2 = id2 )
    ORDER SIBLINGS BY id1, id2
  )
)
GROUP BY id1, id2
ORDER BY MIN( rn );

<强>结果：

 ID1 | ID2
-----------
   1 |   2
   1 |   3
   7 |   3
   2 |   4
   2 |   5
   6 |   5
   4 |   7

<强>更新：

Oracle查询：

SELECT id1,
       id2,
       DENSE_RANK() OVER ( ORDER BY grp_id ) AS grp_id
FROM   (
  SELECT id1,
         id2,
         grp_id,
         ROW_NUMBER() OVER ( PARTITION BY id1, id2 ORDER BY rn ) AS first_row
  FROM   (
    SELECT id1,
           id2,
           grp_id,
           ROWNUM AS rn
    FROM   (
      SELECT id1,
             id2,
             CONNECT_BY_ROOT( rn ) AS grp_id
      FROM   (
        SELECT id1,
               id2,
               ROWNUM AS rn
        FROM   (
          SELECT id1,
                 id2
          FROM   table_name
          ORDER BY id1, id2
        )
      )
      CONNECT BY NOCYCLE
         ( PRIOR id1 = id1 AND PRIOR id2 < id2 )
      OR ( PRIOR id1 < id1 AND PRIOR id2 = id2 )
      ORDER SIBLINGS BY id1, id2
    )
  )
  ORDER BY rn
)
WHERE first_row = 1;

<强>结果：

 ID1 | ID2 | GRP_ID 
--------------------
   1 |   2 |      1
   1 |   3 |      1
   7 |   3 |      1
   2 |   4 |      2
   2 |   5 |      2
   6 |   5 |      2
   4 |   7 |      3

Answer 3

你走了。

SELECT id1, id2 
FROM table 
ORDER BY id2,id1

结果如下：

this link

SQL按顺序依次排序两列

3 个答案: